1. Field of the Invention
The present invention relates to a head cleaning device for use with a disk-type data storage unit which includes a disk-shaped data storage medium and a read/write head for accessing the disk-shaped data storage medium.
2. Description of the Relevant Art
At present, various optical or magnetic disk-type data storage units are widely used with computers, word processors, electronic still cameras, and other information processing systems. The disk-type data storage units generally comprise a mechanism for rotating a disk-shaped data storage medium, a read/write head for writing data on and/or reading data from the disk-shaped data storage medium, and a mechanism for controlling the position of the read/write head with respect to the disk-shaped data storage medium.
The disk-type data storage units are classified into a contact-type data storage system such as a floppy disk drive in which the read/write head is held in physical contact with the data storage disk during read or write operations, and a non-contact-type data storage system such as a hard disk drive in which the read/write head is held out of physical contact with the data storage disk during such operations. In such a contact-type data storage system, the read/write head tends to get dirty and lose its function during usage over a long period of time.
One typical contact-type data storage system is a floppy disk drive. A diskette for use with the floppy disk drive comprises a flexible disk of plastic film coated on its surface with a mixture of a powdery magnetic material and a binder. While the diskette is in use, the surface of the coated layer of the mixture on the flexible disk is held in contact with and abraded by a magnetic read/write head, thereby producing the magnetic material powder. The magnetic powder is attached to and deposited on the read/write head, gradually reducing its reading and writing capabilities.
Although the magnetic heads in magnetic tape recorders may be also degraded in performance by magnetic tapes running in abrasive contact with the magnetic heads, they can easily be cleaned by the user because the magnetic heads are accessible to the user. However, the read/write heads of the floppy disk drives require a dedicated cleaning device because the user has no direct access to the read/write heads.
One conventional cleaning device for the read/write heads of floppy disk drives comprises a cleaning disk similar to a magnetic disk of an actual diskette which can be used in the floppy disk drives, and a jacket similar in shape and identical in dimensions to a jacket of the actual diskette. The cleaning disk is made of nonwoven fabric, for example, for wiping the read/write heads.
In use, the cleaning device is inserted into the slot of a floppy disk drive, the head of which is to be cleaned, in the same manner as an actual diskette. When the floppy disk drive is instructed to effect any one of its normal operations, it rotates the cleaning disk which wipes the read/write head that is held in contact with the surface of the cleaning disk. Since no data is recorded on and hence retrieved from, the cleaning disk, the floppy disk drive stops its operation after the elapse of a certain period of time. If the floppy disk drive is connected to a computer or a word processor, then the display of the computer or the word processor may display an error message indicating that the disk inserted in the floppy disk drive is inappropriate. The read/write head is cleaned by the cleaning disk during the time after the floppy disk drive has started operating and before it stops operating.
This conventional head cleaning device has several problems. Although as the floppy disk drive is in operation during the cleaning process the head may be moved radially with respect to the cleaning disk, the radial movement of the head usually does not exceed one reciprocating movement in a single cleaning cycle, and does not produce a substantial cleaning effect. Actually, a cleaning effect is mostly obtained when the read/write head is wiped in a certain constant direction by a limited region on the cleaning disk, which corresponds to one particular track on an actual diskette that is accessed by the head during normal operation of the floppy disk drive.
The constant direction in which the head is wiped by the cleaning disk is the same as the direction in which the surface of a magnetic disk of any actual diskette slides on the head, i.e., a direction tangential to the track where the head and the magnetic disk contact each other.
The fact that the head is wiped by only the limited region on the cleaning disk results in a relatively short period of time for which the cleaning disk and hence the cleaning device can be used. Therefore, the cost for use of such cleaning device is relatively expensive. Further, the head is not effectively cleaned by the cleaning disk which wipes the head in the constant direction. Specifically, the head usually has a gap defined in its contact surface with diskettes for efficiently magnetically reading or writing data. In most cases, the gap extends in a direction normal to the direction tangential to a track which is contacted by the head. Any powdery deposit of magnetic material which is trapped in the gap cannot sufficiently be removed by the cleaning disk which wipes the head in the constant direction, i.e., the direction normal to the direction in which the gap extends.